Exemplary embodiments of the present invention relate to a steering arrangement.
In existing steering direct screwing of the bottom of the steering spindle with the steering coupling is only possible in the combined field of exhaust gas assemblies, catalytic converters, engines and transmission lines with considerable effort. Here, the steering spindle is screwed in at the bottom with the steering coupling transverse to the steering spindle direction. This has the disadvantage of poor accessibility, and on the other hand the number of variants for optimizing the accessibility for different engine types and steering assemblies, for example left-hand and right-hand drive steering models, is increased, and, in addition, standard assembly sequences, such as the time of assembling the exhaust gas assembly, are hardly or not at all adhered to. Due to the poor accessibility, the screwing can only be carried out by the worker in a highly laborious manner, and takes up a large amount of assembly time. Here, the risk exists that the required screw will slip and be dropped by the worker, whereupon this must then be looked for and found for reasons of production safety. In this case, the assembly procedure is interrupted, which entails a considerable amount of time. In another approach, the steering coupling part is dispensed with and only the steering spindle at the bottom is used, wherein, however, a start-up of the engine in the Z direction during the final assembly, and thus the conflation of the pre-assembled engine/transmission and chassis unit, is, disadvantageously, not possible.
German patent document DE 10 2008 006 497 A1 describes an assembly arrangement for connecting a steering spindle to a steering coupling. The end piece of the steering spindle is inserted into an end receiving region of the steering coupling, wherein the assembly arrangement comprises a device for fundamentally achieving the coaxial alignment of the steering spindle and the steering coupling. This allows the automatic conflation of the steering spindle with the steering coupling, since a manual, coaxial alignment of the steering spindle and the steering coupling can be avoided. To that end, the steering spindle has a hooking element at the end, into which a strap loop protruding from the end receiving region of the steering coupling is mounted before the final assembly. By pulling on the loop of the strap, the hooking element, together with the end piece of the steering spindle, is inserted into the end receiving region of the steering coupling so as to be screwed in there.
Furthermore, German patent document DE 102 39 202 B4 discloses a connection between a steering shaft and a steering gear in a motor vehicle with a divisible joint, whereby the assembly and disassembly processes are simplified. To that end, the joint has an extension that can be fed, for assembly, through an opening in the footwell of the motor vehicle and which is equipped with protrusions, the joint can be inserted without rotation into a moveable cup-shaped or tulip-shaped receiver, which is located outside the footwell relative to the extension and which extends in the direction of the footwell. The joint is designed as a tripod joint, wherein the extension has a tripod head with three segments extending radially away from the extensions, the segments engaging with corresponding grooves of the receiver.
Due to the tight construction space conditions, the steering train normally impedes the assembly of the engine module with the body. In order to simplify the assembly of the engine module an intermediate piece, which connects the steering coupling to the end of the steering spindle, can be provided that enables this to be able to be swiveled away in the loose state, i.e. unscrewed, at the interface at which it is screwed in with the end of the steering spindle. The steering spindle can be pushed back to some extent in the steering wheel direction. After the assembly of the engine, the intermediate piece must be reconnected to the end of the steering spindle. This is extremely difficult for the assembler, since the construction space for a manual operation leaves hardly any clearance and the connection partners are very difficult to detect optically.
Exemplary embodiments of the invention are directed not only to simplifying the conflation of steering spindle end and steering coupling, but an arrangement that enables the conflated steering spindle and steering coupling ends to be connected to each other in the correct relative position and thus for a defective assembly to be prevented.
According to the invention, a steering arrangement contains a steering spindle and a steering coupling provided with a fork crown. The latter bears a connecting element, by means of which an end of the steering spindle is connected to the steering coupling in the form of a plug connection. The steering spindle end and the connecting element are formed as coaxial plug partners at ends facing each other, by means of a tongue and groove guide element pair, which provides a torque-transmitting priority control. Each plug partner, steering spindle end and connecting element thus has at least one groove or one corresponding tongue configured as a guide element. The connecting element is formed by a hollow shaft of the steering coupling, wherein the at least one groove and/or the at least one tongue of the guide element pair is molded onto the interior of the shaft. In addition, the steering arrangement contains a clamping device, by means of which the plug partners can be clamped against each other in a plugging position so that they cannot come loose.
Due to the guide elements according to the invention, which can be readily touched and/or seen by an assembler, the steering spindle and the connecting element of the coupling may, in an advantageously simpler manner, be combined, wherein they always assume the correct relative position to each other due to the pre-determined guiding as a result of the respective correspondence between groove and tongue. The clamping device connects the plug partners by means of contact pressure force in such a way that the plug connection is without clearance and an undesired release of the plug partners from the plugging position during the vehicle operation is prevented. The guide elements formed by tongue and groove extend solely along the steering spindle axle. Therefore, a clamp-free manageability of the plug partners, which is easy for the assembler to embody, is enabled for achieving the plug connection. It is possible, if required, to carry out the assembly by hand.
Due to the fact that the hollow shaft that already exists in the typical steering coupling, to which the fork crown connects, serves as a plug partner, additional components that provide guiding in a straight line can be dispensed with. The groove(s) and/or tongue(s) can be molded onto the hollow shaft in a simple manner.
The shaft is preferably designed as a casting or as a reshaped hollow profile, wherein both are connected unreleasably to the fork crown. This is, for example, achieved by means of a welded joint, in particular a laser-welded joint. The casting and hollow profile can preferably consist of metal, whereby the welded joint can be embodied in a simple manner. It is also conceivable for the casting to be an injection-molded part and to be injected onto the fork crown, should this permit torque transmission with operational safety. Due to the single-piece design of the welded joint, this can subsequently be surface-coated in its entirety. This was not possible in hitherto existing embodiments, wherein the functionality of the plug connection between tongue and groove was set in separate components.
The steering spindle and the connecting element preferably have several tongue and groove guide element pairs displaced towards the periphery, which are designed with different widths and/or are distributed asymmetrically over the periphery of the steering spindle and the connecting element. A clear allocation of the tongue/groove guide elements of the plug partners is hereby possible, such that a defined relative position of the steering spindle end and the connecting element with respect to each other is defined and no defective plug connection can take place during assembly. In the case of an asymmetrical arrangement, three respective grooves and tongues can preferably be arranged on the cylindrical exterior of the steering spindle end and the interior of the connecting element, which are positioned with 120° displacement to one another. The number of grooves can thus be greater than the number of tongues, such that, for each tongue of the connecting element, at least one groove is present on the steering spindle end. Naturally, it is generally also conceivable to provide the grooves in the connecting element and the tongues on the steering spindle end, or to arrange both on both plug partners interchangeably. With a plurality of grooves and tongues, the ability of the plug partners to transmit higher levels of torque is also improved.
The groove and tongue of the at least one tongue and groove guide element pair particularly preferably has a tapered shape, wherein the groove tapers in the longitudinal axial direction towards the side facing away from the plug partner, and the tongue tapers in the longitudinal axial direction towards the side facing the plug partner. When there is tension, the tapers are pulled against each other, whereby, due to the unfolding wedge clamping, a particularly strong positive fit is formed, which leads to a tight and stiff, clearance-free connection of both plug partners. The release protection of the plug partners is also improved by this positive fit. Moreover, clearance is prevented by the spring-loaded tapered joint, said clearance being able to arise when the plug partners wear out.
The shaft of the steering coupling particularly preferably bears the clamping device. This contains a locating sleeve, a pressure spring and a supporting ring. The supporting ring is connected tightly to the shaft of the steering coupling and is mounted coaxially on the end thereof. The connection advantageously takes place by an expansion of the hollow shaft, as a whole or locally. The metallic supporting ring here has recesses with which the hollow shaft can engage with protrusions and is positively wedged in the recesses, whereby a rotational movement and an axial movement of the supporting ring is prevented on the hollow shaft and a defined, fixed position on the shaft is adjusted. As a result of the radial expansion, an additional frictional connection between the shaft and the supporting ring is achieved, which further improves the durability of the supporting ring on the shaft. The pressure spring, preferably designed as a helical spring, lies on the side of the supporting ring facing away from the plugging direction of the steering spindle. The tension is achieved via the pressure spring. The locating sleeve engages behind the supporting ring and the pressure spring is moveably arranged on the shaft for rotation and displacement, wherein it possesses an axial stop on the pressure spring. The locating sleeve has, on the end facing away from the pressure spring, at least one projection pointing radially inwards or a groove that corresponds with the groove or with the tongue of the steering spindle end. Furthermore, an undercut is formed on the end of the steering spindle, which the at least one groove and/or the at least one tongue of the steering spindle end adjoins. The undercut can be a stepped ridge or an annular groove or even a rounded, conical tapering of the steering spindle end.
In order to advantageously achieve the tension, the locating sleeve is raised axially against the elastic force after the plug connection of both plug partners has been achieved, wherein, for example, the projection(s) slide(s) through the grooves of the steering spindle end until the undercut has been reached. After this, the sleeve can be rotated, whereupon the projection(s) can be placed behind a tongue of the steering spindle end by means of a rotation of the sleeve. The sleeve is then unclasped, whereupon it strikes the tongue(s) below with the projection(s). The pressure spring is released, pulling the plug partners together and thereby clamping them.
In a preferred embodiment, the locating sleeve has an annular collar arranged at the end, which extrudes inwards on the side facing away from the pressure spring, which encloses the supporting ring as a cover. The annular collar preferably has the width of the supporting ring and completely covers it. The at least one projection projects radially inwards from this annular collar. The annular collar furthermore has—with respect to its width when situated approximately in the center—at least one opening into which a pin is immersed, which is arranged on the front side of the supporting ring facing away from the pressure spring. The pin is arranged in the covered region of the supporting ring. The opening(s) on the annular collar is/are arranged with displacement in the peripheral direction to the projection or projections in such a way that, when there is immersion of the pin into the opening, the adjacent projection behind adjoins a tongue. In the case of three openings that are arranged with 120° displacement to one another, the adjacent projections are each displaced by 45° to these in the peripheral direction. When the sleeve is rotated, the pin(s) rise(s) on the interior of the annular collar until it/they is/are immersed into the opening. Then, it is not only guaranteed that the projection of the sleeve has struck behind a tongue of the steering spindle end, but also that the clamping is virtually locked by immersing the pin into the opening, i.e. a release-protected clamping is achieved and undesired disassembly is practically no longer possible. The opening and pin can be coordinated in such a way that their shape and dimensions correspond to each other, such that the pin is immersed into the opening in a defined manner and a direct positive fit, and thus a defined position of the pin, is provided in the opening. During immersion, the pressure spring is released yet further, which can be seen in a noticeable snap release that can be detected audibly and tactilely by the assembler.
The length of the pin is preferably not only such that it is immersed into the opening, but also such that it protrudes from the other end. The assembler can thus also haptically detect whether the assembly is complete. When the protruding pin is touched, the clamping is completely finished and the assembly process is concluded. In the case that, for whatever reason, it is necessary for a specific rotary position of the sleeve relative to the supporting ring to be included, it is conceivable for the pins and, accordingly, the openings, to have different shapes, such that a pin can be allocated to an opening precisely without there being any mispositioning.
The clamping device preferably contains a control ring, which adjoins the pressure spring opposite the supporting ring and which has at least one, preferably ramp-like, control contour on the front side facing away from the supporting ring, which the locating sleeve adjoins with a control cam. The control ring has, on its inner periphery, at least one guiding pin, which engages with a guiding groove running axially on the outside of the shaft. The control ring is thus arranged without rotation and can only be moved axially, wherein one groove end with respect to the fork crown forms a stop for the control ring. With three guiding pins that are arranged with 120° displacement on the control ring and engage with one respective guiding groove allocated thereto, the control ring can be guided without tilting. In other words, the shaft accordingly has three guiding grooves, which are also arranged with 120° displacement to one another in the peripheral direction. In an advantageous manner in terms of manufacturing, the respective guiding groove is formed by the channel-like exterior of a tongue of the tongue/groove guide element pair caused when the shaft is impressed. The control ring now forms a counter-stop for the pressure spring with respect to the supporting ring. Due to the installation of the locating sleeve over the at least one control cam, which is formed on the end facing away from the annular collar, the pressure spring is held indirectly on the locating sleeve. Due to its installation, the locating sleeve is held axially tightly to the control ring via the guiding grooves. Due to the formation of a control contour, preferably ramp-like or helical, the twisting of the locating sleeve to the locking position after reaching the undercut is simplified. The further the control cam of the locating sleeve approaches the supporting ring on the ramped route, the more the pressure spring is released and the smoother the rotational movement is until the pins of the supporting ring snap into the openings. Due to the progressive release, the severity of the snapping-in is alleviated, which improves the longevity of the cooperative components of the steering arrangement.
The control contour has two stops between which the control cam can be moved. Three identically configured control contours are preferably formed on the control ring, which adjoin one another and are loaded with a respective control cam. The control cams are formed on the interior of the locating sleeve and join up flush with the closing edge of the locating sleeve. As a result of this, the control contour of the control ring is covered by the locating sleeve. The stop that the locating sleeve adjoins when in the opening position is preferably formed to be longer than the other stop and serves as a display for the assembly position. In other words, a nose of the stop can be seen protruding beneath the locating sleeve when the locating sleeve is snapped onto the pin of the supporting ring and adjoins the other stop with its control cam. For the worker observing the interface between the steering coupling and the steering spindle only from the side of the fork crown, this also provides an optical response to indicate that the assembly has been carried out correctly. A further simplification of this response can exist in that the locating sleeve is provided with symbols or other markings on its exterior, which denote a locked position and an unlocked position. When there is covering with the nose of the stop, it is then completely clear to the worker, with the locking notification, that the assembly is complete and has been undertaken correctly.
In a preferred embodiment, the locating sleeve has at least one resilient clamping bracket protruding from the inner periphery of the sleeve and rising on the front side of the supporting ring on which the pressure spring is supported. During the driving operation and/or due to material defects, it is conceivable for the pressure spring, designed as a helical spring, to break. To prevent the locating sleeve from being released from its locked position as a result of vibrations caused by driving, the clamping bracket serves as a lock against axial movements resulting from the vibrations.
In a further preferred development of the invention, at least one shallow hollow is formed on the interior of the annular collar of the locating sleeve, which contains the contour of the pin of the supporting ring and into which the pin can be positioned. Transportation safety of the steering coupling with the connecting element is hereby guaranteed from the manufacturing facility to the installation site. Due to the shallow nature of the hollow, the worker can rotate the pin out of the hollow without a large amount of physical exertion; however, the hollow is in turn at such a depth that undesired twisting during delivery is prevented.
In a further, particularly preferred embodiment, the steering arrangement contains an additional allocation device for the grooves and tongues of the plug partners when there are several peripherally-displaced groove and tongue guide element pairs. Indeed, a clear allocation of the grooves and tongues is provided by the aforementioned, corresponding formation of the groove widths or the asymmetrical arrangement of the grooves or additional grooves. However, it can arise that, despite a mispositioning of the plug partners, a threading of the tongues into the grooves, and vice versa, is possible up to a specific degree, i.e. over a limited length. The worker, who is of course not able to completely carry out the threading motion, will attempt to de-thread the plug partners. Due to low clamping effects between the plug partners, this can occur in a particularly cumbersome manner, which takes up the worker's power, patience and time. To confront this potential defect, the steering arrangement is equipped with an allocation device. This device contains contour elements of different shapes, which are formed on the locating sleeve on the end facing away from the fork crown and protrude radially inwards. These are arranged with displacement to the projections and are, just like the projections, connected integrally to the locating sleeve. For example, the contour elements are convexities that are shaped to be more or less shallow.
Furthermore, the allocation device has an orientation pin arranged coaxially pre-assembled on the steering spindle end and possessing negatively-shaped contour elements on the periphery with respect to the contour elements of the locating sleeve. The diameter of the pin with its contour elements is smaller than the diameter of the internal width of the shaft, so that the pin can be pushed into the shaft and does not prevent the plug connection of both plug partners. The pin is dimensioned in such a way that, when inserting the pin into the locating sleeve, the contour elements of the locating sleeve and the pin engage with one another with clearance in compliance with the contours. In the case of mispositioning, an insertion is not possible. Thus, a clear allocation of the plug partners has already been undertaken before the plug connection is made. A cumbersome de-threading in the case of defects is no longer present in any way.
Finally, more contour elements are formed in the same radial position in the tongues of the steering spindle end behind the contour elements of the pin, so as not to prevent a further insertion movement when there is correct positioning between the contour elements of the pin and the sleeve. Here, the contour elements in the tongues are formed in such a way that they can pass by the locating sleeve with clearance to the contour elements.
In a particularly preferred development, the steering arrangement has a plug that is pressed into the end of the hollow steering spindle and seals it tightly. Penetration of dirt and corrosive media into the steering spindle is hereby prevented. In addition, it serves as protection against noises from the further steering train and the engine bay. When embodied practically, the plug is connected integrally to the orientation pin. The plug can thus consist of an elastomer, plastic or an elastic rubber material.
These and other advantages are demonstrated by the description below with reference to the accompanying figures. The reference to the figures in the description serves to support the description and to facilitate understanding of the subject matter. Subject matters or parts of subject matters that are essentially the same or similar can have the same reference numerals added to them. The figures are only a schematic depiction of an embodiment of the invention.